Bug 11503: fix several typos

Bug 11503: fix several typos

This patch corrects several typos: Some reported in Bug 11503, others
found during a systematic spell check of the help files.

To test, examine the changes and confirm that the spelling changes are
correct.

Signed-off-by: Mark Tompsett <mtompset@hotmail.com>
Signed-off-by: Katrin Fischer <Katrin.Fischer.83@web.de>
Signed-off-by: Galen Charlton <gmc@esilibrary.com>
(cherry picked from commit a5c762d491465bcc7ad8d8f5e94ff5c36c172091)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>